Satellite Study: slowing plant growth, 2000-2009

Conventional wisdom holds that plants should thrive when temperatures warm and the growing season lengthens under a changing climate. A 2003 study showed that plant growth indeed increased as temperatures warmed between 1982 and 1999. But when researchers at the University of Montana updated the study for the last decade, 2000–2009, they discovered that even though the decade was the warmest since instrumental recordkeeping began, plant growth slowed.

The study is significant because plants soak up carbon from the atmosphere as they grow. As growth slows, the amount of carbon plants take up slows as well, leaving more carbon in the atmosphere to contribute to climate change. It is also a warning that a warming climate could bring a decrease in food and biofuel production.

Researchers Maozheng Zhou and Steven Running published the work in Science on August 20, 2010. They used data from the Moderate Resolution Imaging Spectroradiometer (MODIS) on NASA’s Terra satellite to monitor plant growth and calculate the total amount of carbon plants store as they grow, a value called net primary productivity. Their results are illustrated in this image, which shows the change in the amount of carbon consumed by plants between 2000 and 2009. Green areas show where plants grew more (and consumed more carbon), and brown areas show where they grew less. The deeper the color, the stronger the trend.

In general plant growth and consequently the amount of carbon plants store increased in the Northern Hemisphere and decreased in the Southern Hemisphere. The difference, say Zhou and Running, is water. Three things limit plant growth: light, water, and temperature. In the Northern Hemisphere, warmer temperatures and a longer growing season allowed plants to grow more. But in the Southern Hemisphere, drought dominated the decade. Higher temperatures dried plants and soil, generally slowing growth. The attached graphs illustrate the direct relationship between drought and the amount of carbon plants absorbed between 2000 and 2009.

During the decade, large-scale droughts, primarily in the Southern Hemisphere, were strong enough to overwhelm increased plant growth in other places, resulting in decreased plant growth overall. While 65 percent of the Northern Hemisphere’s vegetated land had increasing growth, 70 percent of the Southern Hemisphere’s vegetated land had decreasing growth. Added together, global plant growth decreased slightly in the decade, reducing carbon uptake by an estimated 0.55 petagrams, a one percent decrease.

It is too early to tell if the recent decade marks the beginning of a longer term trend in plant growth related to long-term climate change. Climate is defined by patterns seen over longer periods of time, at least 20-30 years. In the previous 20 years (1982–1999), plant growth and the related carbon uptake increased as much as six percent. Regardless, the observed decrease in plant growth between 2000 and 2009 helps researchers better understand how plants might respond to a changing climate.

“We see this as a bit of a surprise, and potentially significant on a policy level because previous interpretations suggested that global warming might actually help plant growth around the world,” Running said. “This is a pretty serious warning that warmer temperatures are not going to endlessly improve plant growth.”

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Interannual shifts in plant productivity (green line) fluctuated in step with shifts in atmospheric carbon dioxide (red line) between 2000 through 2009. Credit: Maosheng Zhao and Steven Running Earth has done an ecological about-face: Global plant productivity that once flourished under warming temperatures and a lengthened growing season is now on the decline, struck by the stress of drought.

NASA-funded researchers Maosheng Zhao and Steven Running, of the University of Montana in Missoula, discovered the global shift during an analysis of NASA satellite data. Compared with a six-percent increase spanning two earlier decades, the recent ten-year decline is slight — just one percent. The shift, however, could impact food security, biofuels, and the global carbon cycle.

“We see this as a bit of a surprise, and potentially significant on a policy level because previous interpretations suggested that global warming might actually help plant growth around the world,” Running said.

“These results are extraordinarily significant because they show that the global net effect of climatic warming on the productivity of terrestrial vegetation need not be positive — as was documented for the 1980’s and 1990’s,” said Diane Wickland, of NASA Headquarters and manager of NASA’s Terrestrial Ecology research program.

Conventional wisdom based on previous research held that land plant productivity was on the rise. A 2003 paper in Science led by then University of Montana scientist Ramakrishna Nemani (now at NASA Ames Research Center, Moffett Field, Calif.) showed that global terrestrial plant productivity increased as much as six percent between 1982 and 1999. That’s because for nearly two decades, temperature, solar radiation and water availability — influenced by climate change — were favorable for growth.

Setting out to update that analysis, Zhao and Running expected to see similar results as global average temperatures have continued to climb. Instead, they found that the impact of regional drought overwhelmed the positive influence of a longer growing season, driving down global plant productivity between 2000 and 2009. The team published their findings Aug. 20 in Science.

“This is a pretty serious warning that warmer temperatures are not going to endlessly improve plant growth,” Running said.

The discovery comes from an analysis of plant productivity data from the Moderate Resolution Imaging Spectroradiometer (MODIS) on NASA’s Terra satellite, combined with growing season climate variables including temperature, solar radiation and water. The plant and climate data are factored into an algorithm that describes constraints on plant growth at different geographical locations.

For example, growth is generally limited in high latitudes by temperature and in deserts by water. But regional limitations can very in their degree of impact on growth throughout the growing season.

Zhao and Running’s analysis showed that since 2000, high-latitude northern hemisphere ecosystems have continued to benefit from warmer temperatures and a longer growing season. But that effect was offset by warming-associated drought that limited growth in the southern hemisphere, resulting in a net global loss of land productivity.

“This past decade’s net decline in terrestrial productivity illustrates that a complex interplay between temperature, rainfall, cloudiness, and carbon dioxide, probably in combination with other factors such as nutrients and land management, will determine future patterns and trends in productivity,” Wickland said.

This narrated video gives an overview of net primary production and the carbon cycle. High-resolution data from the Moderate Resolution Imaging Spectroradiometer, or MODIS, indicate a net decrease in NPP from 2000-2009, as compared to the previous two decades. Credit: NASA/Michelle Williams

Researchers are keen on maintaining a record of the trends into the future. For one reason, plants act as a carbon dioxide “sink,” and shifting plant productivity is linked to shifting levels of the greenhouse gas in the atmosphere. Also, stresses on plant growth could challenge food production.

“The potential that future warming would cause additional declines does not bode well for the ability of the biosphere to support multiple societal demands for agricultural production, fiber needs, and increasingly, biofuel production,” Zhao said.

“Even if the declining trend of the past decade does not continue, managing forests and croplands for multiple benefits to include food production, biofuel harvest, and carbon storage may become exceedingly challenging in light of the possible impacts of such decadal-scale changes,” Wickland said.

99 thoughts on “Satellite Study: slowing plant growth, 2000-2009”

The map shows Productivity Trend from -21 to 20 g/m2. That translates to 0.21 tonnes/ha which foresters use. Annual growth rate ranges from 10 (temperate) to 50+ (trop rain) tonnes/ha. So those trends are on order 1% changes.

“Even if the declining trend of the past decade does not continue, managing forests and croplands for multiple benefits to include food production, biofuel harvest, and carbon storage may become exceedingly challenging in light of the possible impacts of such decadal-scale changes,” Wickland said.

By wonderful coincidence, Wickland, himself, owns no forests or croplands, so his challenge is managing other people’s – at your expense, naturally.

Looks like from the top pic some large tracts of earth were not included in the analysis. There is also the chance to confuse correlation with causation – did the co2 change affect plant growth, was it plants affecting co2, was it temp affecting plants and co2 etc… who really knows?

It has NOT been warming…globally, so the conclusion that C02 does not contribute to plant growth increase is false.
Phil Jones said it has not been warming the last 10-15 yrs, possibly cooling, and the decrease is only 1%??
Sound like C02 is still the king of plant growth.
We too are Carbon life form.

The 2 images shown don’t seem to match up.
In the first one (green brown), Borneo and PNG seem to be losing biomass, whereas in the 2nd image (red green) they seem to be gaining.
Similar in other areas as well, i.e. South and North America and Africa.

Do they account for deforestation and changes in land use? Do they account for the destruction of large irrigation systems that occuring in the middle east? The growth of cities? How many houses and farms cropped up in China over the last 10 years? mmmm…. what about dams, increasing extent of estuarine areas, re-creation of lost wetlands? There are to many factors here to just blame c02

1999…..The shift, however, could impact food security, biofuels, and the global carbon cycle….global terrestrial plant productivity increased as much as six percent between 1982 and 1999….driving down global plant productivity between 2000 and 2009

This looks like it is from PDO. 1976/77 to 1999 PDO was (+). Starting in 1999 PDO went (-). Don Easterbrook has talked about the PDO change and food shortages that have begun:

If you look up the plant hardiness zone maps at USDA, 1960 and 1996, you may notice that the zones have shifted two bands to the south. North Texas for example used to be zone 10 in 1960, but is now zone 8.

But does this satellite check the THICKNESS of the plant growth? You know maybe the plants are actually thicker. They do the same trick for the Ice, saying it’s too thin, so maybe the height of the plants it actually higher as CO2 makes them grow better.

So if you flew a satellite over both plants they would look the same even though it is taller

They can tell all this from a satellite instrument? Looking through cloud cover? Omitting Ocean plankton? Without any 0n site biomass sampling for confirmation? Amazing! How do they do that?!.
This runs contrary to site studies that show an increased water use efficiency with increased CO2 along with increased biomass production.

So growth is slowing. Would that correlate with the slowing of temp increase? Reading the article, if one doesn’t carefully read it, it implies that the biosphere is retreating. Which isn’t the case. Further, it seems to imply there’s less CO2 absorption from the biosphere. But that isn’t the case if the biosphere is still growing.

Mods or Anthony or whomever controls such stuff, a suggestion if I may. It would be easier to read without the redundancy.

REPLY: Sorry, once published it stays, but I will add a page break. -Anthony

I’m going to go out on a limb and suggest there’s a fourth thing plants require to grow, and that is food. Plants, given the other three, will not succeed without the fourth. Not all dirt is equal.

But wait – there’s more. Many plants require symbiosis! Forests require soil fungi, for example, and bacteria. Believe it or not, healthy growing areas require shade, too. And seeds don’t just get up and walk away – they need to be carried and buried. That requires critters.

This is why it takes so long for areas burnt to the subsoil to recover. It all has to work together.

I like that there is a 65% increase in the Northern Hemisphere, and a 70% decrease in the summer hemisphere. That goes along perfectly with Joe Bastardi’s theory that it is just a shift of the warmest temperatures northward. Warmer North, cooler South, more plant growth North, less South. seems natural and not worth any worry

They were very explicit that the SH plant productivity dropped due to DROUGHT not temperature. NH plant productivity increased even though temperatures increased BECAUSE THERE WERE NO DROUGHT CONDITIONS. The only logical conclusion one can draw from this is that temperature increases support plant productivity.

If they wanted to make the case that increased temperature caused the drought conditions, they may be able to make that linkage…. except that the NH didn’t have drought conditions… And I wouldn’t be surprised to learn that global precipitation as a total hasn’t varied much, just natural cycles move the droughts (and floods) around the planet on a regular basis. Much of the North American prairie had severe drought conditions in the “dirty thirties”, long before CO2 had risen significantly, and those conditions have not returned since it has risen significantly. Should I conclude that increased CO2 prevents droughts? The evidence for that is about as strong as the evidence that it caused drought in the SH.

It seems the nitrogen fixation by plants is reduced at high levels of CO2 also; in particular C3 plants. The experiment which refers to this problem with the nitrogen fixation at high concentrations of CO2 was published at http://www.pnas.org/content/101/31/11506.full.pdf

On the other hand, we know that C3 plants growth starts slowing at temperatures above 20-25 °C (Odum, Eugene P. and Barrel, Gary W. Fundamentos de Ecología-Quinta Edición. 2006. International Thompson Editores, S. A. de C. V. México, Distrito Federal. Pp. 48-50). The advantage of C3 plants over C4 plants is that C3 plants survive to cold temperatures. 20 °C is the peak temperature at which the growth of C3 plants is optimum. Below and above this temperature the growth of C3 plants unavoidably slows; even if the CO2 in the environment is abundant.

I have insisted frequently on these failures on plant physiology under diverse shifts on the ecological conditions. The status on this situation is that, on biological problems, we cannot oversimplify from particular experiments, to be precise, in biology we must always have in mind the axiom that says: “The whole is much greater that the sum of its parts”.

Increase the CO2 levels all you want; it still won’t do you any good in the face of a major drought. And just look at that — a hemispheric decadal drought coupled with increasing levels of Antarctic sea ice. Fascinating. Meanwhile, the rest of the planet keeps on greening.

Let’s say Earth’s atmosphere warmed during a time that by happenstance
wetness was widespread and CO2 was increasing. Green plants naturally expand their area and also grow better and are planted where they had been absent for years. Following this the general wetness stalls and shifts to more concentrated areas or to over the oceans. Temperature and CO2 are not changing much but the areal expansion and productivity also stall and begin to regress. Thus, there is a slight overall decrease.

However, it is beyond me how both the prior “good” period of wetness and expansion and the more recent “bad” period of little or no temperature increase along with drought can have the same cause. One will have to produce an argument with multiple twists and turns to fit the facts into a coherent explanation.

Here is another twist. Regarding the time period 1953 to 1993, there is a report on part of the Sahel, here:http://www.eden-foundation.org/project/desertif.html
“ Nowadays Malam Garba’s field is three times larger, but his harvest is only 1/7 of what it used to be 40 years ago. … This is just sufficient for his family. The lower yields have been caused by the destruction of perennials that used to shelter the annuals and contribute to soil fertility.”
The big news then wasn’t global warming, it was “desertification” and the magazines and newspapers and TV were consumed by it. Following this – as explained in this post, and elsewhere, there was a “greening” that now seems to have stopped.
These broad cyclical patterns should not be happening with just slow CO2 growth and global warming. It seems some one a single simple answer and there isn’t one.

Argentina:
By selecting 2009 as end year, those “researchers” get decadal precipitation trend falling down, however, when updating to 2010, there is not much of it.. and more, precipitation is now reaching the levels in the early part of 20th century.

I think that all that was shown by this study was a confirmation of general understanding that water is significant to plant growth, viz:
Northern hemisphere, no drought, increased growth.
Southern hemisphere, drought, reduced growth.
All other considerations being equal.

quote
“These results are extraordinarily significant because they show that the global net effect of climatic warming on the productivity of terrestrial vegetation need not be positive — as was documented for the 1980’s and 1990’s,” said Diane Wickland, of NASA Headquarters and manager of NASA’s Terrestrial Ecology research program.
unquote

Professor Running,

If your analysis is correct (I have no reason to suppose it is not although you will get people who question it — some people will question anything), you have failed to carry your conclusion on to the next question. In a warming world there should be more water vapour (required for the positive water vapour greenhouse feedback that the models use) which one might naively assume means more precipitation, not less. So you have demonstrated that a warming world is dryer.

Any suggestions why? I realise that this is peripheral to biology but climate science is a very flexible discipline — a geology and geophysics doctorate allows one to become the leading expert after all — and the role of the ocean surface (the boundary layer so-called) in the production of biological CCNs puts it firmly in your area of expertise. Cuff a passing post-doc and set him to checking the records of oceanic biological CCNs measured over the last…. well as far back as you can go. Tell him to look at all the CCNs while he’s at it.

Invite me to the Nobel ceremony please.

JF
(Please excuse me from banging on about the Kriegesmarine Hypothesis one more time. The increased surface salinity in the oceans, BTW, seems to show that the reduction in CCNs — leading to precipitation reduction and thus less dilution of the surface waters — is more important than the increased coalescence and thus raining out of clouds. The clouds, in other words, don’t form, rather than form and then rain and thin more rapidly.

If I were an Australian I’d be checking ocean currents to see where the oceanic surface oil and surfactant pollution from India and southern China is going: it won’t all be warming the Andaman Sea and, as those two giants industrialise, the run-off is going to dry the west coast. Hint: look at Australian pan evaporation rates.)

As others have pointed out global temps have not increased over that timeframe. Did they consider the obvious as well, like seasonal variation from hemisphere to hemisphere, land management, agricultural practices generally, crop varieties, general plant variation across hemispheres?

“The plant and climate data are factored into an algorithm that describes constraints on plant growth at different geographical locations.” Are, that all important AlGorerithm, thought this was some kind of contraception technique!

When temperatures rise so less CO2 is adsorbed by the oceans leaving more for plants to feed on. Plants respond to CO2 more than temperature.
Plant growth is governed by many chaotic inputs so why concentrate on but one. This does not seem to be science to me but a system to prove a point and give government more leverage to increase taxes and control our lives.

There didn’t seem to be any on ground confirmation of productivity. Nor were a myriad of crop and growth factors taken into account. In China for example there are less farmers and they are older. Makes a difference. Also there has been a significant increase in population which would lead to forrests being replaced by crops. After all 60 million extra people is an increase of 1 percent. There was a large rise in the cost of nitrogenous fertilizers during this time. Probably the biggest factor is the slowing of the nearly annual productivity improvement in many crops. The green revolution of the 70s has all but petered out.

All in all there are any number of reasons for a 1% decrease in growth none of which include CO2 or temperature.

There have always been variations in crops of any kind which are grown out of doors, in soils and in whatever arrives as weather and a 1% fall in growth must fall within accepted natural variability. And we define those who divine the future from studying chicken entrails as primitives?

They were very explicit that the SH plant productivity dropped due to DROUGHT not temperature. NH plant productivity increased even though temperatures increased BECAUSE THERE WERE NO DROUGHT CONDITIONS. The only logical conclusion one can draw from this is that temperature increases support plant productivity.

I thought this ias well. I remember that the
We see this as a bit of a surprise, and potentially significant on a policy level because previous interpretations suggested that global warming might actually help plant growth around the world,” Running said.

“These results are extraordinarily significant because they show that the global net effect of climatic warming on the productivity of terrestrial vegetation need not be positive — as was documented for the 1980’s and 1990’s,” said Diane Wickland, of NASA Headquarters and manager of NASA’s Terrestrial Ecology research program.

Amazing general statements that are very serious. I thought scientist had to back up their claims, offer other possible explanations, (There are dozens not even mentioned) show the satelite measured warming rates in specific areas, demonstrate that the drought areas were not natural, ( I thought anything less then 30 years is just weather?) show charts and graphs with error bars, given such extrordinary claims. I guess general alarmist statements are the normal now. If we in fact had unusual drought, then without the increase in CO-2 the 1% decline in plant growth would have been greater.

Interestingly A recent paper by Jones (Jones, P.D., D.E. Parker, T.J. Osborn, and K.R. Briffa. 2010. Global and hemispheric temperature anomalies—land and marine instrumental records. In Trends: A Compendium of Data on Global Change. Carbon Dioxide Information Analysis Center, Oak Ridge National Laboratory, U.S. Department of Energy, Oak Ridge, Tenn., U.S.A. doi: 10.3334/CDIAC/cli.002) shows that the Southern Hemisphere is warming significantly more slowly than the Northern.
Yet Zhou and Running’s paper shows reduced (1% over a decade!!) NPP in the South, yet an increase in the WARMER North.
Pretty poor evidence that Global WARMING has an adverse effect.
When you read deeper it is all down to increased drought over the last decade in the Southern Hemisphere.
Of course this is “unprecedented” and all sorts of Doom may follow unless you give us more money to investigate further.

Extrordinary broad alarmist claims from these “scientist”
No other reasons offered, even though their could be dozens.
No detailed explanation of vague alarmist warnings based on a minor 1% decline.
No error bars associated with alarmist warnings.

We’ll be alright. By next summer with the Greenland ice cap melted and replaced by thousands of square miles of grassland, an awful lot of CO2 will have been used up.

Before you bet on that you will have to be sure that there is some well mineralised soil under all that ice, that there is just the right amount of precipitation, that the temperature of the soil is just a little above freezing, that some of that CO2 is floating around over Greenland, and, absolutely vitally, that there is an abundance of ultra violet light shining down on that glorious soil. Temperature, per se, is not the vital plant growth factor. It is the combination of mineral availability, moisture, CO2 and good old sunlight that rule the roost.

This study finished in 2009, this year in the southern hemisphere we have had rain, the drought is over. I have been watching our forests and grassland suffer for years, this year they have quadrupled in growth. In OZ our CSIRO are climate alarmists but have some real scientists still working for them. Some while ago they stated that our country absorbes all our emissions of CO2. The growth we have seen this year most likely sucked in all of Europes too, and a some of Chinas. Australia is blooming.

Come off it! There are less than ten independent data points in the set, with a year to year variation of order +/- 3 times the alleged trend (’04-’05 -6x, ’05-’06 +4x!). That’s not enough even to get an average value to this level, let alone a trend. Note the “how to lie with statistics” trick of suppressing the zero and plotting differences instead (and calling the differences anomalies, when there’s nothing remotely anomalous about them).

Perhaps the rate of increase has decreased because it is not slowing down at all, but not spending up in proportion the level of growth?
A one unit increase in a pool of ten units is dramatic. A one unit increase in a pool of 100 units is a marginal increase, but is still the same amount of growth.

As a long distance hiker, I’ve walked in a lot of places (SoCal, New Mexico, Alaska, Canadian Rockies, Newfoundland, Florida, North Carolina, Montana – just to name a few) over the last 20 years. My only comment is that these people need to get out where the plant growth is actually happening, because it IS happening. I was in Virginia 4 days ago – and the kudzu is lusher than I’ve ever seen it before. Same story everywhere I’ve been for the last few years.

BTW – having worked for 40+ years as a science ops engineer on spacecraft remote sensing instruments like (and including) MODIS/Terra, I’d suggest that the boys need to recalibrate their data.

If one disregard the fact that this is just another calculated guesstimate of made up proxies. Why again has their been so many floods and above normal precipitation in south america this decade, reported even by NASA pretty much every time it is reported, if their conclusion is drought?

And by the way, plants need nutrients and sunlight first, moist and water second, warmth is third because it can get too hot and warmth is not really as necessary other than it not being freezing for too long.

One way to kill a plant is to derive it of sunlight for too long like when it’s too cloudy and it turns pitch black in the under growth where the kid planty grow.

Gee, I wonder if it ever occurred to the authors to compare 2000-2009 temperature anomalies in the southern and northern hemisphere. I thought even cavemen knew that that global warming is a northern hemisphere phenomenon.

So what did the authors find? Northern hemisphere plants grew better and southern hemisphere plants did not.

An important consideration in relation to climate change
is that carbon dioxide fertilization raises the optimum
temperature for photosynthesis (e.g., Norby et al., 2002). It
also increases water use efficiency of plants. However, other
factors, such as deficient nitrogen or absence of moisture, can
limit plant response to increases in carbon dioxide.

Higher level of CO2 will definitely help in a drought. It won’t magically make plants require no water but it does help them use what little water there is more efficiently.

The might even lead one to think that green plants evolved over the course of billions of years where temperatures and CO2 levels were much higher than today and so that is the evironment evolution optimized them around. If one thinks that one would in fact be correct as the geologic column reveals a planet that spent most of its history in warmer with much higher atmospheric CO2.

“The advantage of C3 plants over C4 plants is that C3 plants survive to cold temperatures. 20 °C is the peak temperature at which the growth of C3 plants is optimum. Below and above this temperature the growth of C3 plants unavoidably slows; even if the CO2 in the environment is abundant.”

Yabbut the temperature span around the optimum is pretty wide and both C3 and C$ respond positively to higher CO2 up to at least 2x current levels.

While C3 has an optimum temperature of 20C it doesn’t fall off the peak much at 23C which is where C4 hits its optimum.

The difference of course is, as you stated, C3 plants survive in cold that will kill a C4 plant and C4 plants will survive in heat that will kill a C3 plant.

Yet one fact that stubbornly remains is that global warming isn’t global. It’s regional with the primary beneficiary being the higher northern latitudes where for most of the year it’s too cold for even C3 plants and where early and late frosts can have a devastating effect on agriculture. The warming is happening right where we need warming to happen and it isn’t happening where we don’t need it. What’s to complain about? Global warming and rising CO2 is a wonderful thing.

The potential that future warming would cause additional declines does not bode well for the ability of the biosphere to support multiple societal demands for agricultural production, fiber needs, and increasingly, biofuel production,” Zhao said.
First: This is the same tale for scaring kids. There is no future warming at all, but PRESENT COOLING:http://weather.unisys.com/surface/sst_anom.html
In South America there are two main weather systems: One to the east of the Andean mountains range (altitude up to 7000 m), and other to the west of it. Cold SST means less evaporation in the pacific, but normal at the east side, so the amazon basin will not suffer any droughts. These are to be expected, as in other solar minimums, more to the south, at the argentinian “pampas” plains:
From the known argentinian geologist Miguel Gonzales, in his studies in the “Salinas del bebedero”, a salt lake in Argentinahttp://www.springerlink.com/content/m11m129238u61484/
He studied a dried salt lake called “Salinas del Bebedero”, he found that this salt lake , though then surrounded by dried lands and weather, filled with water during solar
minimums, coming from the east side of the Andes mountains.

Didn’t have time to read all the comments, so this has likely already been said, but:

If the biomass had increased in the last decade, that would have been proof that global warming was proceeding apace.

But the biomas decreased in the last decade (supposedly) and so that becomes evidence that global warming will cause droughts that will eventually have dire consequences for humanity.

The first possibility adds support to the global warming hypothesis while the second assumes global warming. This leaves no possibility of the study reducing support for the global warming hypothesis, an approach likely to keep those research dollars flowing.

But if they were surprised by the reaction of biomass to a warming world, perhaps someday they’ll also be surprised by the reaction of the climate to rising CO2? Maybe both models, that of biomass production and that of the effect on climate of rising CO2 were too simplistic from the outset?

lookimng at that map in red and green.
Australias areas of green?
someone better do that map again and try and get it right!
the green areas across the middle of aus,Sth Aus and victoria, and Tasmania?
all of which have been hard hit by drought for many years.
the coastal fringes in red? when they ARE our food production areas in the main.
sheesh, give a kid a crayon and look what you get!

“During the decade, large-scale droughts, primarily in the Southern Hemisphere, were strong enough to overwhelm increased plant growth in other places, resulting in decreased plant growth overall.”
________________
Let me see if I understand. During the period, h2o was down due to drought, so things didn’t grow well. OK, what does this have to do with co2 intake being down? I don’t get it. Were the waterless plants supposed to suck in just as much co2 even it there was a drought? That doesn’t sound right? Does this mean if there’s a drought that we’re in trouble? Wasn’t that always true? I still don’t get it.

While C3 has an optimum temperature of 20C it doesn’t fall off the peak much at 23C which is where C4 hits its optimum.

What really surprised me is that C4 plants survive at high temperatures, up to 45 °C. The production of C4 plants becomes stable at 20 °C; from there on up to 45 °C the production doesn’t increase but doesn’t decrease either. However, C3 plants offers a production line of Gaussian type, although its minimum is above than that of C4 plants. Corn, a C4 plant, would benefit from the combination “high temperature -high CO2 concentration” but up to some limits, which, according to experimentation, are ~1000 ppmV, on CO2 concentration, and 45 °C, on temperature. However, yet on this case we cannot generalize because of the many varieties of corn.

Yet one fact that stubbornly remains is that global warming isn’t global. It’s regional with the primary beneficiary being the higher northern latitudes where for most of the year it’s too cold for even C3 plants and where early and late frosts can have a devastating effect on agriculture. The warming is happening right where we need warming to happen and it isn’t happening where we don’t need it. What’s to complain about? Global warming and rising CO2 is a wonderful thing.

I agree, rising CO2 and GW are good for life, but limits exist. I consider it is another case where the axiom “The whole is greater than the sum of its parts” applies on, especially when dealing with climatology. For example, we have had a nice mild summer, regarding temperatures. :)

This is what happens when ‘researchers’ draw straight lines through stochastic data and extrapolate to answers they want to get.

The variance is as the paper states – due to lack of rain not temperature. Droughts and floods have come and gone- look at the Murray Darling Basin. But I suppose it all depends on the answer the ‘researcher’ is looking for.

Strange, the Sahel in these pictures is white or the zones bordering it are mostly red. Yet a recent study revealed a serous greening in the last decades. This study also corresponds to the increased rice production reported during recent years in the Sahel. Despite ongoing civil war food production increased.http://news.nationalgeographic.com/news/2009/07/090731-green-sahara.html

“But that effect was offset by warming-associated drought that limited growth in the southern hemisphere, resulting in a net global loss of land productivity.”

The only association is in the malfunctioning minds of propagandists. Cold and Dry OR Warm and Wet. Like I said before watch for the focus to now be on drought and not temperature. During Cooling-Drying the narrative will be about the drying, and during Warming-Dampening, the narrative will be about the warmth. Head I win, Tails you loose!

‘So having no snow on the ground isn’t vitally important to plant growth?’

Actually no. Having snow on the ground during winter is vitally important if you want your damn crop to survive, because the snow isolates from the deep freeze that can freeze the ground down to six feet and that’ll kill the seeds and a seedling. So with snow you get an early start come spring.

Sure. There’s undoubtedly some optimal point for the biosphere as a whole. The thing of it is there doesn’t appear to be enough economically recoverable fossil fuel on the planet to reach the climate optimum by burning it.

Since it’s a reasonable question to ask what is the optimum temperature and CO2 level for the planet I’m going to go ahead and say it was the Early Eocene Climatic Optimum where average temperature was 6C warmer than today and CO2 was around 1800ppm.

‘So having no snow on the ground isn’t vitally important to plant growth?’

Actually no. Having snow on the ground during winter is vitally important if you want your damn crop to survive, because the snow isolates from the deep freeze that can freeze the ground down to six feet and that’ll kill the seeds and a seedling. So with snow you get an early start come spring.

Agriculture in California should really suck according to your thesis. In point of fact California has a very productive agricultural industry.

Close the majority of the world’s temperature measuring stations, guess at missing temperature measurements near the poles, improperly take into consideration UHI effects, throw out any historic cooling trends at specific stations (ie: Orland CA), and adjust the remaining data using 1200-km radius ‘smoothing’ over missing stations, and what have we got? The official world surface temperature record as decided by Dr. James “thumbs on the temperature scale” Hansen, better known as a compedium of corrupted thermal garbage.

This is outrageous climate doublespeak at its worst. Making a travesty of scientific research publishing.

The declining ‘greening’ – if it’s true, and let’s face it, WTFK – is due do lack of warming for ten years (and, no doubt, a myriad other adverse factors affecting the biosphere which ARE due to mankind’s activities). And they say it just goes to show that global warming CAN lead to less food production and global starvation.

They are really taking the p*ss with this one.

Who reads these ‘science journals’ anyway? Oh, that’s right, government advisors all over the planet…

The draught in the southern hemisphere could be because antarctica is increasing in extent while the arctic until recently has been decreasing in extent.Could this explain the divergence between north and south?

Since it’s a reasonable question to ask what is the optimum temperature and CO2 level for the planet I’m going to go ahead and say it was the Early Eocene Climatic Optimum where average temperature was 6C warmer than today and CO2 was around 1800ppm.

Indeed, during the Eocene primates adaptive radiation (speciacion) happened driving 15 species to anthropoids, from which we are one species.

Nevertheless, there is something that worries me, and it is the evolution of species through the last three million years, in particular green plants and phytoplankton. It’s supposed they have adapted to the shifts of climate until present, so the question is if the species that have adapted to many climatic changes in the past would endure a climate change that could take the Earth back to ancient environmental conditions.

Obviously, a climate change of such magnitude, as the one you proposed, would favor biodiversity, but the question is: What species would disappear and what ones would survive which could undergo adaptive radiation?

I was hoping to get an update on how this ‘greening of the earth’ was going, because I figured that the satellites could give a pretty good picture of the health of the biosphere. I had got used to the idea that the CO2 was helping the plants, but I must admit this paper fills out my understanding, that the temperature is actually more important than CO2 levels.

Obviously, a climate change of such magnitude, as the one you proposed, would favor biodiversity, but the question is: What species would disappear and what ones would survive which could undergo adaptive radiation?

Evolution is cleverer than you are. ~Leslie Orgel

A few million years is like yesterday to genetic memory. Any species that can’t adapt to sustained temperatures a few degrees higher than 20th century average is at an evolutionary dead-end anyway. The earth has pretty radical and rapid climate shifts between large scale glaciation and interglacial periods that cycle through in just 100,000 years or so which isn’t enough time for evolution to create novel works of genetic art. The capacity to quickly adapt to changing climate is something that’s inherent in most living things today or they wouldn’t be here.

Species typically enjoy a tenure on average of about 10 million years before going extinct. Genetic entropy inevitably takes its toll and more prototypical members of the phylum then generate something new to fill the empty niche where they then enjoy a limited tenure before their own speciality sends them into extinction. An estimated 99.9% of all species that ever existed have gone extinct. Most if not all of the modern phyla appeared rather suddenly in the Cambrian Explosion 500 mya. Few of those phyla are extinct today but countless evolutionary dead-ends along the way are footnotes in the history of life.

This is just the way of the biological world. Our insults to it are like water off a duck’s back.

I would answer to Orgel: “I hope so… I’m the product of evolution.” :)

The capacity to quickly adapt to changing climate is something that’s inherent in most living things today or they wouldn’t be here.

Species typically enjoy a tenure on average of about 10 million years before going extinct. Genetic entropy inevitably takes its toll and more prototypical members of the phylum then generate something new to fill the empty niche where they then enjoy a limited tenure before their own speciality sends them into extinction. An estimated 99.9% of all species that ever existed have gone extinct. Most if not all of the modern phyla appeared rather suddenly in the Cambrian Explosion 500 mya. Few of those phyla are extinct today but countless evolutionary dead-ends along the way are footnotes in the history of life.

Of course, extinctions favor biodiversity, according to the observations on the paleobiological records. Nonetheless, the solution to the question about what species would survive for radiating after extinctions remains unsolved.

The authors seem to be concerned that they have found evidence that CO2 absorption by plants will be reduced. I downloaded the monthly CO2 data from: http://www.esrl.noaa.gov/gmd/ccgg/trends/ and looked at the CO2 variation per year. First I detrended the data by subtracting off a 2nd order polynomial fit and then took the difference between the maximum and minimum for each year to find the yearly change. Ave range= 6.26 ppm, std. dev. 0.5

Changes in the ocean temperature probably is more important for CO2 absorption, but there is no evidence in the monthly CO2 data that there has been a decrease in CO2 uptake by plants as some of the CO2 variation is due to the yearly growing season with most of the land mass in the northern hemisphere.

SULFUR
Airborne Sulfur scatters light, which is more efficiently used by plants than direct light.
This is not just an excuse for the “Deliberate Cooling with high-altitude Sulphur Plan”, that so many have advocated (Lovelock, author of the Gaia Theory, “Dr. Ozone” Paul Crutzen, Ken Caldiera, ex-leader of the Opposition to it, the presidential GW advisor, etc.). Sulfur Cuts are a more likely cause for the starving of Millions every year with high Food Prices, than Ethanol (corn prices are not high enough, or affect Foreign Countrysides enough to explain rises that seem higher than the CAUSE). And Fishing Patterns have long been favoring the Boneless fishes over the Boned, and as Fish Bones rot & release Sulfur Dimethyls …
PS: the Bones themselves doubtless are the “mising CO2 sink” – – because the IPCC & the entire Atmospheric Modeling Community mistook the Geological process called Isostasy, for a long way of saying that water dissolves bones. Geologists do teach that, but FIRST you have to accumulate 1000s of feet thickness, form rock, rear the Sea Floor up into a Mountain range … THEN the action of H2O falling rain, moving quickly on downslopes, in gullies & streams — EROSION — in short, dissolves the CALCIUM CARBONATE.
250 million years later.
The IPCC assumes it is IMMEDIATE.
… Fishing pattern changes (at-sea Nurseries called No-Fish Zones) can restore sulfur a bit. … I’ve never seen numbers on the tonnage of Dimethyl REDUCTION — only that Natural Sulfur — volcanos are a relatively small part of the total — exceeds the man-made.
>> This raises the question of whether the MASSIVE cuts in Su “pollution” combined with the fishing patterns reducing NATURAL sources – – may have reduced the Planet BELOW the pre-industrial Sulfur levels ! DANGER !!!
Didn’t plant growth increase, by so much in the Mt. Pinutubo (high sulfur) year ,that CO2 gain dropped a factor of 5 ???

These critters haven’t been around for billions of years because they’re weak and unable to adapt. It’s ludicrous to think a slightly lower ocean pH is going to do any significant harm to the primary producers. Now it turns out the goofy things can survive for years in a vacuum. Even I’m impressed by that.

For those not wanting to read the article the little beasties did it by circling the wagons. They formed a ball and those in the center survived. That’s actually fairly common instinctive behavior for everything under attack from phytoplankton to elephants to pioneers travelling west in covered wagons. :-)

Nonetheless, the solution to the question about what species would survive for radiating after extinctions remains unsolved.

Indeed it does remain unsolved. All, none, or something in between. Evolutionary biology and climatology are similar in that both only make educated guesses about the future based upon the past.

There’s a disclaimer commonly made when talking about a company’s economic prospects for the future: Past performance is guarantee of future performance. I have a comeback for that: Yet it remains the best predictor we have.

So based on past performance in warmer higher CO2 climes I’m more inclined to predict all or most extant species will survive but population sizes will shift downwards for some and upwards for others with the net result being much greater biomass and biodiversity.